Note: Descriptions are shown in the official language in which they were submitted.
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DISPERSION OF HARDPHASE PARTICLES IN AN INFILTRANT
[0001]
STATEMENT REGARDING FEDERALLY SPONSORED
RESEARCH OR DEVELOPMENT
[0002] Not applicable.
BACKGROUND
Field of the Invention
[0003] The invention relates generally to earth-boring drill bits used to
drill a borehole for the
ultimate recovery of oil, gas, or minerals. More particularly, the invention
relates to improved,
longer-lasting matrix and impregnated bit bodies. Still more particularly, the
present invention
relates to providing composite hard particle matrix materials with improved
erosion resistance.
Background of the Invention
[0004] An earth-boring drill bit is typically mounted on the lower end of a
drill string and is
rotated by rotating the drill string at the surface or by actuation of
downhole motors or turbines,
or by both methods. With weight applied to the drill string, the rotating
drill bit engages the
earthen formation and proceeds to form a borehole along a predetermined path
toward a target
zone. The borehole thus created will have a diameter generally equal to the
diameter or "gage"
of the drill bit.
[0005] The cost of drilling a borehole for recovery of hydrocarbons is very
high, and is
proportional to the length of time it takes to drill to the desired depth and
location. The time
required to drill the well, in turn, is affected by the number of times the
drill bit must be
changed before reaching the targeted formation. This is the case because each
time the bit is
changed, the entire string of drill pipe, which may be miles long, must be
retrieved from the
borehole, section by section. Once the drill string has been retrieved and the
new bit installed,
the bit must be lowered to the bottom of the borehole on the drill string,
which again must be
constructed section by section. This process, known as a "trip" of the drill
string, requires
considerable time, effort and expense. Accordingly, it is desirable to employ
drill bits which
will drill faster and longer. The length of time that a drill bit may be
employed before it must
be changed depends upon a variety of factors, including the bit's rate of
penetration ("ROP"),
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as well as its durability or ability to maintain a high or acceptable ROP. In
turn, ROP and
durability are dependent upon a number of factors, including the ability of
the bit body to resist
abrasion, erosion, and wear.
[0006] Bit performance is often limited by selective erosive damage to the bit
body.
Decreasing the erosive wear of bit bodies increases the footage per bit run
and maintains the
design intent of cutter exposure for optimal cutting, and hydraulic flow
paths, and also reduces
the propensity of lost cutters and junk in the hole.
[0007] Two predominant types of drill bits are roller cone bits and fixed
cutter bits, also known
as rotary drag bits. A common fixed cutter bit has a plurality of blades
angularly spaced about
the bit face. The blades generally project radially outward along the bit body
and form flow
channels there between. Further, cutter elements are typically mounted on the
blades. The FC
(fixed cutter) bit body may be formed from steel or from a composite material
referred to as
matrix.
[0008] To improve the erosion resistance of steel bit bodies, a protective
hardfacing coating is
often applied, where a harder or tougher material is applied to a base metal
of the bit body. An
example of a hardfacing is described in US 2010/0276208 Al; in which the
maximum
thickness of the hardphase of the protective coating is stated as limited to
about 210p.m. Other
thin coatings, typically less than about 0.500 m, like HVOF( high velocity
oxygen fuel)
sprayed and electrolytic coatings with co-deposition of micron size hardphase,
have also been
used on FC steel bits to reduce erosive body wear. The effectiveness of a FC
steel body bit in
erosive applications is dependent on the coating integrity. Coating failure
and exposure of the
steel body can lead to accelerated erosive damage effecting bit performance
and dull condition
of bit.
[0009] The propensity of steel body bits to experience erosive damage when in
service has
been a primary reason for the use of FC matrix bits. Such matrix bit bodies
typically are
formed by integrally bonding or embedding a steel blank in a hard particulate
(or hardphase)
material volume, such as particles of WC (tungsten carbide), WC/W2C (cast
carbide) or
mixtures of both, and infiltrating the hardphase with a infiltrant binder (or
infiltrant).
[0010] In fabricating such bit bodies, the cavity of a graphite mold is filled
with a hardphase
particulate material around a preformed steel blank positioned in the mold.
The mold is then
vibrated to increase the packing of the hardphase particles in the mold
cavity. An infiltrant,
such as a copper alloy is melted, and the hardphase particulate material is
infiltrated with the
molten alloy. The mold is cooled and solidifies the infiltrant, forming a
composite matrix
material, within which the steel blank is integrally bonded.
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The composite matrix bit body is removed from the mold and secured to a steel
shank having a
threaded end adapter to mate with the end of the drill string. PDC cutters are
then bonded to
the face of the bit in pockets that were cast.
[0011] PDC matrix bit bodies suffer from erosion during many drilling
applications, and the
damage to the blades and gage of such bits is often so extensive it cannot be
repaired.
[0012] A conventional matrix body bit is typically comprised of hardphase
particles of
macrocrystalline WC or cast carbide of combinations thereof. The particle size
distributions are
typically optimized to provide high powder packing with tap densities of about
10.0 g/cc and
hardphase particle size distributions typically range from 80 Mesh (1771.trn)
to 625 Mesh
(201.tm). The maximum particle size used in a conventional hardphase is
typically 180[tm with
a typical average size of 50 m. The size of the particles make them prone to
pullout in erosive
applications, hence the matrix is prone to wear and erosive damage. A more
erosion resistant
material would therefore improve the dull condition of such bits, and allow
longer runs, more
runs per bit body, and improved repairability.
[0013] DuraShellTM is surface enhancement coating, developed to reduce erosion
of matrix
bits. The coating has a bi-modal hardphase distribution of large cast carbide
particles of about
6001.im comprising about 65 wt % and 100 p.m spherical cast carbide particles
comprising about
35 wt%. A uniform distribution of hardphase constituents is produced by the
use of a fugitive
binder which typically comprises about 3 wt% of the hardphase mix. Figure 1,
depicts the
position of erosion on a typical bit crown indicated by shaded areas, as such
the mix is
selectively applied to the corresponding areas on a mold surface (erosion
resistant mix
formulations can be applied to internal cavities within the bit, such as
nozzle bores and to gage
locations for erosion protection). The mold is then loaded with conventional
hardphase powder
and infiltrated with an alloy. The resultant bit body comprises selectively
placed integral
bonded surface enhancements, on the bit body where erosion is likely to occur.
[0014] Figure 2 however, shows the microstructure of the integral bonded
surface
enhancement and exemplifies that the erosion resistance of the integral bonded
surface
enhancement is limited by preferential wear of the matrix binder due to its
reduced hardness
(typically about 125 VHN). The matrix therefore wears most quickly, exposing
the hardphase
particles leading to particle pull out and or cracking and fracturing of the
surface. Therefore,
there is a need to reduced the wear rate of the matrix and provide effective
erosion resistance of
such large particle surface enhancements.
[0015] Diamond shell surface enhancement coating, is another example of a
surface
enhancement developed with the aim of reducing erosion of matrix bits. The
coating has a bi-
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modal hardphase distribution, comprising of about 15 wt % of 500nm particles
of diamond grit
and about 85 wt% of macrocrystalline WC with an average particle size of about
50 m. A
uniform distribution of hardphase constituents is produced via the use of a
fugitive binder
which comprises about 3 wt % of the mix. The mix is selectively applied to
areas of a mold
surface where the bit body is prone to erosion. The mold is then loaded with a
conventional
hardphase powder and infiltrated with a Cu alloy. The resultant bit body
comprises selectively
placed diamond surface enhancements located on the bit body where erosion is
likely to occur.
[0016] The diamond enhancement however, is limited by wear to the Cu alloy
matrix binder
(typical harness of 150 VHN) and subsequent pullout of the hardphase
particles. Therefore it
would be desirable to increase the hardness of the matrix, thereby reduce
matrix wear rate and
provide more effective erosion resistance of the large particle diamond
surface enhancement.
[0017] The use of cemented carbide particles (for example WC-Co, WC-Ni, Metal-
Carbide or
combinations thereof) in composite matrix materials has typically been limited
because when
infiltrant interacts with the cemented carbide, a decrease in hardness of the
resultant matrix is
observed. The decrease in hardness is due in part to the increase in the mean
free path of the
hardphase after the cast body is cooled, and subsequent ease of pull out of
the hardphase from
the matrix.
[0018] The degradation of a commercially available matrix powder, (M2001 by
Kennametal
with MF53 copper alloy infiltrant) is shown in Figure 3. The WC-Co cemented
carbide particle
had a pre-infiltration hardness of about 1300 VHN, which degraded to about 800
VHN on
interaction with the infiltrant. Figure 3, shows that the addition of a molten
infiltrant to a dense
hardphase of cemented hardphase particles results in a bloated hardphase
within the matrix.
The cemented hardphase particles post infiltration are typically 2 to 3 times
larger in size than
the cemented hardphase particles prior to infiltration.
[0019] Fixed-cutter bits comprised of infiltrated hardphase composites are
further disclosed in
U.S. patent numbers: 6,98,4454, 3,149,411, 3,175,260, and 5,589,268. An
example of a matrix
composite using cemented carbide hardphase where degradation of the hard
component was a
concern is documented in U.S. Pat. No. 3,149,411. Infiltrant alloy chemistry
was used to limit
the degradation of the cemented carbide particles by using infiltrant alloys
containing a metal
from Group VIII, Series 4 of the Periodic Table (i.e., iron, cobalt or nickel)
and minor amounts
of chromium and boron.
[0020] Another example of a hardphase composite is documented in U.S. Pat. No.
3,175,260,
where particles of cemented tungsten carbide or tungsten carbide alloy were
heated and the
molten matrix metal infiltrant poured into the mold containing the hard
particles allowing the
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infiltrant to infiltrate the interstices of a mass of the hardphase. The
melting point of the
infiltrant ranged between about 1550 F (843 C) and 2400 F (1316 C) and
decreasing the
infiltration temperature and time was used as a method to suppress the
interaction between the
cemented carbide hardphase and the infiltrant during infiltration.
[0021] An example of selective placement of discrete inlays of hardphases with
compositions
that differ from the bulk material of the matrix body of a fixed cutter matrix
bit are disclosed in
U.S. Pat. No. 5,589,268 and U.S. Pat. 5,733,664. The art further discloses the
fabrication of a
composite comprising at least one discrete hardphase element held by a matrix
powder wherein
an infiltrant was infiltrated into the hard components.
[0022] One disclosed infiltrant was a copper-nickel-zinc alloy identified as
MACROFILTM
65, which has a melting point of about 1100 C. Another disclosed infiltrant
was a copper-
manganese-nickel-zinc-boron-silicon alloy identified as MACROFILTM 53, having
a melting
point of about 1204 C. The art did not disclose a way to selectively use
surface enhancements
to increase erosion resistance.
[0023] U.S. patent No. 6984454 discloses a wear-resistant member that includes
a hard
composite member that is securely affixed to at least a portion of a support
member. The hard
composite is comprised of a plurality of hard components within a mold where
an infiltrant
alloy that has been infiltrated into the mass of the hard components.
[0024] The hard composite member disclosed in U.S. patent No. 6984454,
consisted of
multiple discrete hard constituents distributed in the composite member, the
discrete hard
constituents comprised one or more of: sintered cemented tungsten carbide, and
a binder
included one or more of cobalt, nickel, iron and molybdenum, coated sintered
cemented
tungsten carbide wherein a binder includes one or more of cobalt, nickel, iron
and
molybdenum, and the coating comprises one or more of nickel, cobalt, iron and
molybdenum,
and a matrix powder comprising hard particles wherein most of the hard
particles of the matrix
powder have a smaller size than the hard constituents. The infiltrant alloy
employed had a
melting point between about 500 C to about 1400 C, and was infiltrated under
heat into a
mixture of the discrete hard constituents and the matrix powder so as to not
effectively degrade
the hard constituents upon infiltration. The hard constituents and the matrix
powder and the
infiltrant alloy were bonded together to form the hard composite member.
However,
degradation of the cemented carbide constituent was disclosed as an issue.
[0025] U.S. Pat. No. 6,045,750 discloses that a functional composite material
for a steel bit
roller cone body with erosion resistant wear surface enhancements can be
achieved with high
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hardphase particle loading (high volume fraction), of about 75 volume %, and
large constituent
cemented carbide particle size by powder forging (solid state densification)
cones The surface
enhancement coating thickness in this case is limited in thickness to about
three times the
hardphase particle diameter and is constrained by the surface roughness or the
texture of
coating.
[0026] It is also known that powder-forged hard composite inlays, elements, or
components
with high cemented carbide loading and large constituent particles offer
enhanced performance
when used as cutting edges and wear surfaces in drill bits and other earth-
engaging equipment.
However, levels of achievable hard phase volume fractions are limited by
geometric constraints
on powder packing and by deformation/fracture behavior of particles during the
forge cycle. In
particular, coarse particle size fractions needed for maximizing packing
density and wear
resistance tend to bridge during forge densification, leading to voids and
particle fracture
defects in the densified composite. These problems are mitigated by
formulation of powder
preforms with at least one sintered cemented carbide particulate constituent
of a composition,
size, and residual porosity that imparts preferential plastic deformation and
densification at
forging temperature under local conditions of elevated pressure associated
with particle
contacts.
[0027] This functionality is provided by formulating a steel matrix of the
hard composite using
iron powder in the preform with a particle size less than 20 micrometers, in
conjunction with
the deformable partially porous sintered cemented carbide particulate
constituent having a
particle size that is between 5 to 100 micrometers. If the deformable sintered
cemented carbide
particulate constituent also has a nickel binder and another sintered cemented
carbide hard
phase constituent comprises a cobalt binder, useful strengthening of the
matrix will be realized
through the formation of tempered martensite halos around the cobalt binder
carbide phase(s),
due to nickel and cobalt diffusion and alloying of the surrounding iron
matrix. The resulting
hard composite microstructure exhibits increased resistance to the shear
localization
failure/wear progression [as disclosed in U.S. Pat. Appl. No. 2011/0031028
Al]. This
publication, however is limited to steel body fixed cutter bit enhancements.
[0028] Hence, conventional FC composite materials that use large hardphase
particle sizes to
increase erosion resistance, often are limited by preferential matrix (binder)
wear due to particle
pullout and subsequent cracking and chipping damage to expose the primary
large particles of
the hard phase during service. Thus, a need exists for composite materials for
use in bit body
matrices and wear surfaces on drill bits and other earth-engaging equipment
that provide
surface enhancements with increased erosion resistance to improve bit
performance in
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demanding downhole applications, thereby increasing bit footage/run, providing
significantly
better looking dulls, maintaining design intent of cutter exposure and
hydraulic flow paths
during the run and reducing risk of lost cutters in the hole.
[0029] As such, embodiments disclosed herein address the requirement for
improved erosion
resistance in composites used in bit body matrices and wear surfaces on drill
bits and other
earth-engaging equipment, as compared to certain conventional composites used
and known in
the art.
BRIEF SUMMARY OF THE DISCLOSED EMBODIMENTS
[0030] These and other needs in the art are addressed in one embodiment of the
present
invention by a composite material comprising: a first pre-infiltrated
hardphase constituent; at
least a second pre-infiltrated hardphase constituent. The second pre-
infiltrated hardphase
constituent is a porous carbide which comprises at least 0.5 weight % of a
binder and at least
about 1% porosity.
[0031] The composite material also comprises an infiltrant. In some
embodiments the
composite material further comprises a third pre-infiltrated hardphase
constituent. In some
embodiments of the composite material, the second pre-infiltrated hardphase
constituent is a
partially sintered cemented tungsten carbide. In other embodiments, the second
pre-infiltrated
hardphase constituent is 83WC-17Ni. In still further embodiments of the
composite material,
the second pre-infiltrated hardphase constituent comprises about 1% to about
5% porosity. In
further embodiments of the composite material the infiltrant comprises at
least one of Al, Co,
Cr, Ni, Fe, Mg, Zn, and Cu.
[0032] In some embodiments a method of making a composite material comprises:
mixing; a
first pre-infiltrated hardphase constituent; a second pre-infiltrated
hardphase constituent; and a
fugitive binder to form a mixture. Loading the mixture into a coupon mold; and
adding matrix
powder to said mold; further adding infiltrant to said mold; superheating the
infiltrant; and
disintegrating the second pre-infiltrated hardphase constituent in the
infiltrant, forming a
dispersion of first pre-infiltrated hardphase and disintegrated second pre-
infiltrated hardphase
constituents within the binder infiltrant; and cooling the dispersion to form
the composite
material.
[0033] Other embodiments comprise a drill bit for drilling a borehole in
earthen formations
comprising: a bit body having a composite material. The composite material
comprises; a first
pre-infiltrated hardphase constituent; and a second pre-infiltrated hardphase
constituent. The
second pre-infiltrated hardphase constituent is a carbide which comprises at
least 0.5 weight %
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of a binder and at least about 1% porosity. The composite material further
comprises an
infiltrant.
[0034] Thus, embodiments described herein comprise a combination of features
and
characteristics intended to address various shortcomings associated with
certain prior drill bits,
cutting elements, wear surfaces, hard particle matrix composites, and methods
of using the
same. The various features and characteristics described above, as well as
others, will be
readily apparent to those skilled in the art upon reading the following
detailed description, and
by referring to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] For a detailed description of the disclosed embodiments of the
invention, reference
will now be made to the accompanying drawings, wherein:
[0036] Figure 1 depicts a perspective view of a bit crown;
[0037] Figure 2 depicts a micrograph of DurashellTM surface enhancement made
in accordance
with the prior art;
[0038] Figure 3 depicts a light photo-micrographic image of M2001 hardphase
matrix
microstructure made in accordance with the prior art;
[0039] Figure 4 is a perspective view of an embodiment of a bit made in
accordance with
principles described herein;
[0040] Figure 5 is a top view of the bit shown in Figure 4;
[0041] Figure 6 is a perspective view of the bit shown in Figure 4;
[0042] Figure 7 is a view of one of the blades of the drill bit of Figure 4;
[0043] Figure 8 depicts a representation of the hardphase constituents of a
composite material
prior to infiltration (A) and after infiltration (B), made in accordance with
principles described
herein;
[0044] Figure 9 depicts a process flow chart representing a method for making
a hard particle
matrix composite material in accordance with principles described herein;
[0045] Figures 10A, 10B, and 10C are light photo-micrographic images at
resolutions of
400um, 40um and 4um of a composite material comprising a first pre-infiltrated
(spherical cast
carbide) hardphase constituent, a second pre-infiltrated hardphase constituent
(83WC-17Ni)
and a third (spherical cast carbide) hardphase constituent within a binder
infiltrant, made in
accordance with principles described herein; Figures 10D, 10E and 1OF are
light
photomicrograph images at resolutions of 400um, 40um and 4um of a composite
comprising a
first pre-infiltrated (irregular crushed carbide) hardphase constituent, a
second pre-infiltrated
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hardphase constituent (83WC-17Ni) and a third (irregular crushed carbide)
hardphase constituent
within an infiltrant, also made in accordance with principles described
herein.
DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS
[0046] The following discussion is directed to various exemplary
embodiments of the
invention.
[0047] The drawing figures are not necessarily to scale. Certain features
and components
herein may be shown exaggerated in scale or in somewhat schematic form and
some details of
conventional elements may be omitted in interest of clarity and conciseness.
[0048] In the following discussion and in the claims, the terms "including"
and "comprising" are
used in an open-ended fashion, and thus should be interpreted to mean
"including, but not limited
to... ." As used herein, the term "about," when used in conjunction with a
percentage or other
numerical amount, means plus or minus 10% of that percentage or other
numerical amount. For
example, the term "about 80%," would encompass 80% plus or minus 8%.
[00049] Further, throughout the following discussion and in the claims, herein
a composite
material maybe also described as a hardmetal composite material, a hardmetal
matrix composite
material, a hardmetal infiltrant composite material, a hard particle composite
material, a hard
particle matrix composite material, a hard particle matrix material, a hard
particle infiltrant
composite material, a hardphase composite material, a hardphase matrix
composite material and a
hardphase infiltrant composite material. Also, a matrix binder maybe referred
to as a binder
infiltrant or infiltrant. A matrix that is formed by the action of a molten
matrix binder on hardmetal,
hardphase or hard particle constituents may also be described as a matrix that
is formed by the
action of a molten binder infiltrant on hardmetal, hardphase or hard particle
constituents.
[0050] Referring to Figures 4 and 5, exemplary drill bit 10 is a fixed cutter
PDC bit adapted for
drilling through formations of rock to form a borehole. Bit 10 generally
includes a bit body 12, a
shank 13 attached to a threaded connection or pin 14 for connecting bit 10 to
a drill string (not
shown). Bit face 20 supports a cutting structure 15 and is formed on the end
of the bit 10 that faces
the formation and is generally opposite pin end 16. Bit 10 further includes a
central axis 11 about
which bit 10 rotates in the cutting direction represented by arrow 18.
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[0051] Cutting structure 15 is provided on face 20 of bit 10 and includes a
plurality of blades
which extend from bit face 20. In the embodiment illustrated in Figures 4 and
5, cutting
structure 15 includes six blades 31, 32, 33, 34, 35, and 36. In this
embodiment, the blades are
integrally formed as part of, and extend from, bit body 12 and bit face 20,
and blades 31, 32, 33
and blades 34, 35, 36 are separated by drilling fluid flow courses 19.
Referring still to Figures 4
and 5, each blade, includes a cutter-supporting surface 42 or 52 for mounting
a plurality of cutter
elements. Bit 10 further includes gage pads 51 of substantially equal axial
length measured
generally parallel to bit axis 11. Gage pads 51 are disposed about the
circumference of bit 10 at
angularly spaced locations. In this embodiment, gage pads 51 are integrally
formed as part of the
bit body 12.
[0052] Gage-facing surface 60 of gage pads 51 abut the sidewall of the
borehole during
drilling. The pads can help maintain the size of the borehole by a rubbing
action when cutter
elements 40 wear slightly under gage. Gage pads 51 also help stabilize bit 10
against vibration.
In certain embodiments, gage pads 51 include flush-mounted or protruding
cutter elements 51a
embedded in gage pads to resist pad wear and assist in reaming the side wall.
Cutter element 40
comprises a cutting face 44 attached to an elongated and generally cylindrical
support member
or substrate which is received and secured in a pocket formed in the surface
of the blade to
which it is fixed. Cutting
face 44, in the embodiment shown, comprises a polycrystalline
diamond material. In general, each cutter element may have any suitable size
and geometry.
[0053] In the embodiment shown, bit body 12 is formed from a composite
material. Referring
now to Figure 6 and Figure 7, bit body 12 has a gage facing surface 60, which
may be
hardfaced with a hard particle matrix composite. Hardfacing is applied at
positions lA and 1B
and other such locations on the bit body that succumb to wear.
[0054] Embodiments herein are further drawn to a composite material
comprising, a first pre-
infiltrated hardphase constituent, and at least a second pre-infiltrated
hardphase constituent. The
second pre-infiltrated hardphase constituent is a porous carbide which
comprises at least 0.5
weight % of a binder and at least about 1% porosity. The composite material
also comprises an
infiltrant.
[0055] Embodiments herein are further drawn to the composite material wherein
the second
pre-infiltrated hardphase constituent is configured to disintegrate in the
infiltrant.
[0056] In some embodiments, the first pre-infiltrated hardphase constituent is
selected from the
group comprising titanium carbide, tantalum carbide, tungsten carbide,
cemented tungsten
carbides, cast tungsten carbides, sintered cemented tungsten carbide,
partially sintered
cemented tungsten carbide, silicon carbide, diamond, and cubic boron nitride.
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[0057] In some embodiments, the first pre-infiltrated hardphase constituent is
tungsten carbide.
In some further embodiments the tungsten carbide may be either in the form of
WC and/or
W2C. Tungsten carbides may comprise: spherical cast WC/W2C, cast and crushed
WC/W2C
(irregular) and macro-crystalline WC. For hardness properties, the spherical
cast WC/W2C has
greater hardness than cast and crushed WC/W2C, which in turn has greater
hardness than
macro-crystalline WC. For toughness properties, the Spherical Cast WC/W2C has
a lower
toughness than cast and crushed WC/W2C, which in turn has a lower toughness
than Macro-
crystalline WC.
[0058] In some embodiments, the second pre-infiltrated hardphase constituent
comprises a
porous carbide, selected from the group comprising boron carbide, silicon
carbide, titanium
carbide, tantalum carbide, chromium carbide, vanadium carbide, zirconium
carbide hafnium
carbide, molybdenum carbide, niobium carbide, tungsten carbide, cemented
tungsten carbide,
partially sintered cemented tungsten carbide, spherical cast carbide, and
crushed cast carbide. In
some embodiments the second pre-infiltrated hardphase constituent is a
partially sintered
cemented tungsten carbide. In some embodiments the second pre-infiltrated
hardphase
constituent is a partially sintered cemented tungsten carbide.
[0059] In other embodiments of the composite material, the second pre-
infiltrated hardphase
constituent further comprises a binder. In some further embodiments the second
pre-infiltrated
hardphase constituent is comprised of at least 0.5 weight % of a binder. In
other embodiments
the second pre-infiltrated hardphase constituent is comprised of about 0.1 to
about 50 weight
percent of the first binder. In further embodiments the binder comprises about
15 to about 25
weight percent of the second pre-infiltrated hardphase constituent and in a
further still
embodiment the binder comprises about 17 weight percent of the second pre-
infiltrated
hardphase constituent.
[0060] In some embodiments of the composite material, the binder is at least
one of: Al, B, Ni,
Co, Cr, Cu, and Fe, and in some further embodiments the binder is Ni. In some
embodiments of
the composite material, the second pre-infiltrated hardphase constituent is
83WC-17Ni.
[0061] In some embodiments of the composite material, the second pre-
infiltrated hardphase
constituent comprises about 1% to about 50% porosity. In some other
embodiments the second
pre-infiltrated hardphase constituent comprises about 1% to about 10%
porosity, and in some
further embodiments the second pre-infiltrated hardphase constituent comprises
about 1% to
about 5% porosity. In another embodiment the second pre-infiltrated hardphase
constituent
comprises at least about 1% porosity.
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[0062] In some embodiments, the constituents of the composite material may
have a bimodal
or multimodal particle size distribution. In some embodiments the first pre-
infiltrated hardphase
constituent has an average particle size of about 50 p.m to about 1200 p.m,
and in some further
embodiments the first pre-infiltrated hardphase constituent has an average
particle size of about
300 p.m to about 900 p.m.
[0063] In other embodiments of the composite, the second pre-infiltrated
hardphase constituent
has a particle size of about <1p.m to about 300 p.m. In further embodiments,
the second pre-
infiltrated hardphase constituent has a particle size of about 5 p.m to about
100 m, and in some
further still embodiments, the second pre-infiltrated hardphase constituent
has a particle size of
about 15 p.m to about 60p.m.
[0064] In some embodiments, the composite material comprises a third pre-
infiltrated
hardphase constituent. In some embodiments, a third pre-infiltrated hardphase
may be further
selected from the group comprising boron carbide, silicon carbide, titanium
carbide, tantalum
carbide, chromium carbide, vanadium carbide, zirconium carbide hafnium
carbide,
molybdenum carbide, niobium carbide, tungsten carbide, cemented tungsten
carbide, partially
sintered cemented tungsten carbide, spherical cast carbide, and crushed cast
carbide.
[0065] In some instances, the third pre-infiltrated hardphase constituent has
an average particle
size of about 1 p.m to about 500p.m. In other instances, the third pre-
infiltrated hardphase
constituent has an average particle size of about lp.m to about 100p.m and in
further instances
the third pre-infiltrated hardphase constituent has an average particle size
of about 1 p.m to
about 65p.m.
[0066] In other embodiments, the composite material comprises an infiltrant.
In some
embodiments of composite material, the infiltrant comprises at least one of
Al, B, Ni, Co, Cr,
Fe, and alloys thereof In some further embodiments, the infiltrant is Co.
[0067] In other embodiments of the composite material, the first pre-
infiltrated hardphase
constituent comprises a first pre-infiltrated hardphase constituent binder
[FPHC-binder], in
some embodiments FPHC-binder comprises at least one of Al, B, Ni, Co, Cr, Fe,
and alloys
thereof, in some other embodiments the FPHC-binder is Co.
[0068] In other embodiments of the composite material, the third pre-
infiltrated hardphase
constituent comprises a third pre-infiltrated hardphase constituent binder
[TPHC-binder], in
some embodiments FPHC-binder comprises at least one of Al, B, Ni, Co, Cr, Fe
and alloys
thereof, in some other embodiments the TPHC-binder is Co.
[0069] In some embodiments, a second pre-infiltrated hardphase constituent is
selected, that in
comparison to the first pre-infiltrated hardphase constituent (and in some
embodiments also in
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comparison to a third pre-infiltrated hardphase constituent) has: a small
particle size, high
residual porosity, and high binder content. The small particle size allows the
second pre-
infiltrated hardphase constituent to enter the interstitial spaces that are
present between the
large particles of the first, or the third pre-infiltrated hardphase
constituents or combinations
thereof In some embodiments, the second pre-infiltrated hardphase constituent
is a partially
sintered tungsten carbide, which is particulate in structure, and comprises
voids due to reduced
crystal to crystal growth, and is thus porous. The partially sintered tungsten
carbide also has
high binder content, for example 17 weight % in 83WC-17Ni. The Ni binder is
superheated on
contact with a molten infiltrant. In some embodiments, the Ni binder undergoes
thermal
expansion which causes swelling of the second pre-infiltrated hardphase
constituent. Without
being limited by this or any theory, the degree of expansion is believed to be
proportional to the
weight percent of Ni.
[0070] As the second pre-infiltrated hardphase constituent expands and
degrades after contact
with the infiltrant, its particulate structure disintegrates within the
infiltrant, forming a
dispersion of relatively small particles among the larger particles of the
first (and optionally
third) pre-infiltrated hardphase constituents.
[0071] Therefore, in some embodiments, smaller more dispersed hardphase
particles of pre-
infiltrated hardphase are formed, and in some other embodiments, WC species
are formed, each
of which are directly embedded in the infiltrant. Thus, in some embodiments of
the composite
material, the size ratio of the second pre-infiltrated hardphase constituent
before infiltration and
after infiltration is 2 to 1, in other embodiments the size ratio of the
second pre-infiltrated
hardphase constituent before infiltration and after infiltration is at least 5
to 1, and in further
embodiments the size ratio of the second pre-infiltrated hardphase constituent
before infiltration
and after infiltration is at least 10 to 1.
[0072] These multiple hardphases (first pre-infiltrated hardhphase constituent
(1), second pre-
infiltrated hardphase constituent (2) and third pre-infiltrated hardphase
constituent (3)) are
represented before infiltration, in Figure 8A and after infiltration in Figure
8B. Figure 8B
depicts the dispersed species (2') formed from the second pre-infiltrated hard
phase constituent
(2), as they occupy interstitial spaces between the larger hardphase
constituents forming a
localized uniform hard phase in the matrix.
[0073] In some embodiments, a uniform hardphase dispersion are formed by the
dispersed
particulate 83WC-17Ni species and the larger hardphase constituents. In some
embodiments a
composite material with a more uniform distribution of hard particles within
an infiltrant as
compared to conventional hard particle matrix composites is formed and in some
embodiments,
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the composite material imparts increased wear and erosion resistance as
compared to some
conventional composite matrix materials.
[0074] In some embodiments a method of making a composite material comprises,
mixing: a
first pre-infiltrated hardphase constituent; a second pre-infiltration
hardphase constituent;
Carbonyl iron powder; methylcellulose (fugitive binder); and water to form a
mixture. The
mixture is then loaded into a coupon mold, desiccated and cooled. Matrix
powder, shoulder
powder and binder infiltrant are further added to the mold, which is loaded
into a preheated
furnace. The infiltrant is superheated and the second pre-infiltrated
hardphase constituent
disintegrated in the infiltrant to form a dispersion of hardphase
constituents. The dispersion is
cooled to form the composite material which is further removed from the mold.
[0075] In some embodiments, desiccating comprises heating the mold at about
325 F for about
1 hour. In other embodiments the mold is cooled to less than about 80 F. In
still further
embodiments superheating comprises maintaining the furnace at about 2100 F for
about 90
minutes.
[0076] In some embodiments, the composite material made by the method
described herein is a
matrix body bit. In some other embodiments, the composite material made by the
method
described herein, may be an impregnated bit body. In further embodiments, the
composite
material made by the methods disclosed herein, may be employed as wear or
erosion resistant
inserts or inlays that are applied to any wear surface of a drill bit or other
earth-boring tool or
device.
[0077] Some embodiments are further drawn to a drill bit for drilling a
borehole in earthen
formations, wherein the bit body is a composite material comprising; a first
pre-infiltrant
hardphase constituent; a second pre-infiltrant hardphase constituent; wherein
the second pre-
infiltrant hardphase constituent is a porous carbide which comprises at least
0.5 weight % of a
first binder and at least 1% porosity; and an infiltrant. In some further
embodiments, the second
pre-infiltrated hardphase constituent is configured to disintegrate in the
infiltrant. In other
embodiments, the more uniform the dispersion of the total hardphase
constituents within the
matrix, the less preferential wear and erosion velocity of the matrix occurs,
thereby prolonging
the life of the bit or wear surface.
[0078] The following examples, conditions and parameters are given for the
purpose of
illustrating certain exemplary embodiments of the present invention.
EXAMPLES
Example 1: Production of Composite Material A
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[0079] A composite material (A) was produced by the methods described herein,
and by the
process depicted in Figure 9. A first pre-infiltrated hardphase constituent
(spherical cast
tungsten carbide) comprising a particle size range of 500um to 850 um, a
second pre-infiltrated
hardphase constituent (partially sintered cemented carbide WC83-17Ni),
comprising particles
ranging in size from 20um to 53 um and a third pre-infiltrated hardphase
constituent (spherical
cast tungsten carbide) comprising a particle size range of 60um to 160um, were
mixed with
carbonyl iron powder, methylcellulose (fugitive binder) and distilled water
and loaded into a
coupon mold.
[0080] The mold was placed in an oven and desiccated at 325 F for 1 hour,
removed from the
oven and allowed to cool to < 80 F. Hard matrix powder and shoulder powder
were added to
the mold and packed. A Copper infiltrant alloy (powder) was further added to
the mold. A
furnace was preheated to 2150 F, the mold was placed in the furnace and the
temperature
maintained at 2100 F for 90 minutes.
[0081] The mold was removed and directionally cooled using a full contact
vermiculite cool.
The resulting in situ dispersed composite material was then removed from the
mold. The
microstructure of the composite is presented in the light photomicrographs of
Figures 10A, 10B
and 10C. A trimodal distribution of post-infiltrated hardphase particles is
produced, which
gives a more uniform dispersion of hard particles. The second pre-infiltration
hardphase
constituent disintegrates within the molten infiltrant and disperses locally,
and within the larger
hardphases forming a more uniform hardphase within the matrix as compared with
some
conventional composite materials. The Vickers hardness of the composite matrix
was measured
and found to be 114 VHN for virgin matrix without hard particle dispersion and
335 VHN for
matrix with in situ dispersed hardphase particle.
Example 2: Production of Composite Material B
[0082] A composite material (B) was produced by the methods described herein
and by the
process depicted in Figure 9, whereby a first pre-infiltrated hardphase
constituent of irregular
crushed cast tungsten carbide comprising a particle size range of 420 um to
840 um, a second
pre-infiltrated hardphase constituent of partially sintered cemented carbide
83WC-17Ni,
comprising particles ranging in size from 20um to 53 um, and a third pre-
infiltration hardphase
constituent of irregular crushed cast tungsten carbide comprising a particle
size range of 74um
to 177um, were mixed with carbonyl iron powder, methylcellulose (fugitive
binder) and
distilled water and loaded into a coupon mold. The mold was placed in an oven
and desiccated
at 325 F for 1 hour, removed from the oven and allowed to cool to < 80 F.
Matrix powder was
then added to the mold, the powder packed and shoulder powder added. A Cu
(Copper) alloy
CA 02852007 2016-02-01
infiltrant (powder) was further added to the mold. A furnace was preheated to
2150 F, the mold
placed in the furnace and the temperature maintained at 2100 F for 90 minutes.
[0083] The mold was removed from the furnace and directionally cooled, using a
full contact
vermiculite cool. The resulting in situ dispersed composite material was then
removed from the
mold. The microstructure of the composite is presented in the light
photomicrographs of Figures
10D, 10E and 10F. Again a trimodal distribution of hardphases is produced,
with a more uniform
dispersion within the matrix. The hardness of the composite matrix was
measured and found to be
174 VI-IN for virgin matrix without hard particle dispersion and 319 WIN for
matrix with in situ
dispersed hardphase particle.
100841 Therefore it is believed that the composite materials made by the
methods described
herein and exemplified in Example 1 and Example 2, will impart to matrix and
impregnated drill
bit bodies and wear surfaces improved wear and erosion resistance as compared
to some
conventional composite materials, matrix and impregnated bit bodies and wear
surfaces.
100851 The scope of the claims should not be limited by the preferred
embodiments set forth in
the examples, but should be given the broadest purposive construction
consistent with the
description as a whole.
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